The study published in The Lancet medical journal says there is strong evidence to show that a lack of activity increases the risk for everything from heart disease and type 2 diabetes to breast and colon cancers, and the study says, it shortens life expectancy.

WebMD quotes researcher Dr. I-Min Lee, an epidemiologist at Harvard's School of Public Health saying, "Physical inactivity has a large impact on the health of the world. In fact, its impact is comparable to that of cigarette smoking."

The numbers are staggering, suggesting 1 out of every 10 deaths worldwide can be attributed to a lack of exercise and researchers say it is so bad it needs to be treated as a pandemic. The BBC reports, the team of 33 researchers who took part in the study, say governments need to warn people about the dangers rather than just reminding people of the health benefits.

The Lancet published the study as part of a series on physical activity in the run-up to the London Olympics.

ABC News says American researchers suggest that not spending at least 150 minutes a week doing some form of moderate physical activity like brisk walking for 30 minutes is responsible for between 6 and 10 percent of heart disease, diabetes and cancer. Dr. Lee suggests if everyone started doing at least 30 minutes of exercise every day, life expectancy around the world would increase by 0.68 years. A separate Lancet study estimates as many as 1 in 3 adults and 4 out of 5 teens between the ages of 13 and 15 are not getting enough exercise.

Dr. James Levine, professor of medicine at the Mayo Clinic in Minnesota tells WebMD "This is a super, super analysis." "We know that as soon as somebody gets out of their chair, their blood sugar improves, their blood cholesterol and triglycerides improve, and that's very consistent. Every time you get up it gets better. Every time you sit down it gets worse."

But not everyone is buying the results. Dr. Timothy Armstrong from the World Health Organization in Switzerland says the WHO estimates inactivity causes fewer deaths worldwide, only 3.2 million compared to the 5.7 million estimated in the study. He thinks the Lancet researchers compared numbers that were collected two different ways. However he tells WebMD, "That is not to say that physical activity or physical inactivity is not a major risk factor. It is. WHO currently ranks it fourth after high blood pressure, tobacco use, and high cholesterol."

Whatever numbers you believe, the bottom line is, one of the best things you can do for your long term health is to get up out of that chair and get moving.